DIY Davits

[4arch]

We'd like to add dinghy davits to our boat but aren't too keen on spending the $1500 new ones cost with all the trimmings. Any ideas or designs for home brew units? Ideally they would look halfway decent also.

[brantleychuck]

Get used ones. Fort myers craigs list has them pretty regularly


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[newhaul]

Google diy dingy davits found many pictures to design off of.

[4arch]

Originally Posted by newhaul

Google diy dingy davits found many pictures to design off of.

Appreciate the suggestion but what I'm finding so far are mostly commercially available units. Since I don't know how to weld stainless or aluminum, to copy an existing design would be difficult without having to hire out some of the fabrication - which would probably end up not achieving any cost savings.

I'm more curious whether anyone has had any luck stick building davits with off the shelf components?

[model 10]

One route is to buy something like 11/2" tube, AL or stainless. Buy a tubing rolling/ bender from Harbor Fright ($150) and roll a bend in a couple of straight lengths of tube or get a muffler shop to do it. Your bends might look better but way more expensive and a LOT more trouble. Their type bender puts a depression in the bend sometimes. If you practice, you can smash the ends in a nice looking manner using a big vice or a press and using some bits of of round stock to give the smashed part a nice radius. After that it's all about bending up some flat stock for the bases and buying some blocks for the upper ends. You will need to add some struts here and there to make it less wobbly. These could be some 1" stainless tubes through bolted and/or using regular 1" fittings for something like a dodger
Almost every city has a surplus metal dealer so material should sell for way less than new. Just a thought...

[newhaul]

If you are going to bend your own tube fill it with dry sand before you bend it pack it in. That will help prevent the kinking or flattening spots then dump it out after you are done bending the pipes.

[colemj]

Davits are not something to play around with or go cheap on. Building your own, if you weld and use a good design and materials is one thing, but trying to piece something together on the cheap without welding and using inexpensive materials will lead you to a world of hurt. Unless you have the smallest, lightest dinghy, and never plan to use those davits while sailing, it can actually be dangerous for both you and your boat.

I know this will get the $500/month crowd and the DIY'ers in an uproar, but this is the truth. Don't stick build davits out of cheap material, put a dinghy on them and head out sailing - you will find trouble.

Mark

[model 10]

Originally Posted by newhaul

If you are going to bend your own tube fill it with dry sand before you bend it pack it in. That will help prevent the kinking or flattening spots then dump it out after you are done bending the pipes.

Good point. If done well, you can make bends without a bender. The sand has to be packed really tight. Big leaguers use casting sand. Unfortunately you often need to weld up the ends so the sand stays put. I've tried it with thin tube and had no luck.

[Hudson Force]

There are many pipefitters working in industry that are skilled craftsmen. I found a pipefitter who made my 2.5" diameter stainless steel davits in his garage. My davits are far stronger and less expensive than those I see on the regular marine market.

[newhaul]

Mark I wholeheartedly agree with you davits are not a place to scrimp on and I'm a big contributed to the 500 croud spend good money the first time its cheaper than loosing the tender when on passage. Get a local welder to make you some as a side job they may do it at cost plus a lil for his time

[colemj]

Originally Posted by Hudson Force

There are many pipefitters working in industry that are skilled craftsmen. I found a pipefitter who made my 2.5" diameter stainless steel davits in his garage. My davits are far stronger and less expensive than those I see on the regular marine market.

This is the way to do it "cheap" - find a skilled professional who works for a reasonable wage, buy proper materials and use a good strong design.

It still won't be cheap - I wouldn't think proper davits, materials and mounting will be <$1,000.

Yours possibly was lower price because it looks like you didn't need much height or overhang and had a strong place for mounts already. This part will be highly boat-dependent.

Mark

[4arch]

For better or worse, it’s just part of my nature to always want to first try to reinvent the wheel before buying the ready-made solution. So if we boil this down to engineering 101, the task would be to build a corrosion resistant L-shaped arm about 3’ high with a 3 foot extension to support a 300 lb. static load using only off-the-shelf parts and no welds, no custom made fittings, and minimal bends. I don’t see a reason why this isn’t achievable, although the results may not be aesthetically pleasing or lightweight. A lot of outboard lifting cranes are actually stick built with a vertical pole, C-shaped channel on the top, and some kind of connecting strut.

That said, I count at least five companies making davits in the Kato/Garhauer style (double bent stainless tubes with intermediate webbing of either smaller diameter stainless tubes or plates) all selling for around the same price point. So clearly the design has its merits and there are enough willing buyers to sell them as priced.

[colemj]

I don't think you have enough experience with using davits. A 300lb static load is the least of the issue. If you plan on sailing with that 300lbs in the davits, the dynamic loads are tremendous and not applied in the load directions most davits are designed to lift in. And that is in good weather.

An engine lift is a poor example to follow because it's purpose is to vertically lift a load and place it on a fixed point - not carry that load while sailing.

You wouldn't believe how many of the production davit kits that screw into a deck and partially supported by stanchions I have seen bent and tore out of boats once they start sailing with them in rougher conditions. BTW, those davits are welded joints, not ones made of bimini fittings fixed with set screws, or similar.

BTW, have you even priced proper materials for this type of project. I doubt you could even get the stainless tubing alone for <$500 - and that will be 304 grade and unpolished.

But my advice is worth what you are paying me for it, so go ahead with anything that floats your boat (or sinks it in this case... ).

Mark

[4arch]

Originally Posted by colemj

I don't think you have enough experience with using davits. A 300lb static load is the least of the issue. If you plan on sailing with that 300lbs in the davits, the dynamic loads are tremendous and not applied in the load directions most davits are designed to lift in. And that is in good weather.

I have exactly zero experience and that's why I'm posting here before jumping in with both feet. I want to do it right, but I also want to get the best value for my dollar.

Originally Posted by colemj

You wouldn't believe how many of the production davit kits that screw into a deck and partially supported by stanchions I have seen bent and tore out of boats once they start sailing with them in rougher conditions. BTW, those davits are welded joints, not ones made of bimini fittings fixed with set screws, or similar.

If davit kits aren't even any good, what is the alternative? I don't imagine the davit companies are going to take on the responsibility of engineering the connections. This goes back to the value question. If I pay $1500 for a ready made product and it still fails, it's not a good value proposition.

[colemj]

The davit kits are OK, but require proper mounting. Most simply screw them into the deck and attach the supports to weakly mounted stanchions - then stick 300# dinghies on them and go to sea. Mounted correctly, and used correctly, they are an OK solution.

Best is what Hudson Force did - find a skilled professional and have them make strong davits with a good design. Pay attention to providing strong mounting points.

However, this will cost money. Not just for the labor, but for the material. I can't picture any decent davit system made without welds and from inexpensive material.

The Oceanis 400 is a very popular boat. There must be many of them who have installed davits. Look there for workable designs and mounting ideas. Pay particular attention to strong mounting.

Mark